The present invention relates to an assembled cam shaft for an internal combustion engine, and more particularly to an assembled cam shaft in which a cam lobe and a journal are made of sintered alloys and conjoined to a steel shaft member.
As for a conventional assembled cam shaft in which a cam lobe, a journal member and so forth are separately manufactured and conjoined to a steel shaft member, most of the cam shaft elements such as the journal and gears except the cam lobe are made of steel. Although it is relatively easy to perform finishing work on the steel, various production steps may be required for joining the journal etc. to the steel shaft member due to machining of such mechanical parts and brazing or the like. For that reason, the manufacture of the cam shaft is rather costly. Further, wear resistance of a sliding portion made of steel is low, especially when the portion is used as the journal.
Copending U.S. patent applications have been filed bearing Ser. Nos. 722,223 and 722,224. Further, sintered alloys for use internal comubstion engines are described for example in U.S. Pat. Nos. 4,388,114, 4,491,477, 4,345,943, 4,363,662, 4,505,988 and 4,334,926.